The probe found that officers misinterpreted the man's slow actions as resisting arrest and mistook his efforts to keep his pants up as reaching for a gun.

Charges against the man were dropped.

Spoerl admitted to violating the police department's Taser policy during the traffic stop. Investigators also determined that he used a level of force that was not reasonable or necessary, that he failed to give a warning he was about to use his Taser, and that he filed an inaccurate and ambiguous report about the incident.

Three of the officers, including Spoerl, were suspended for five days without pay and ordered to undergo retraining. The officer who initiated the traffic stop, Michael Rahn, falsified a report about the incident and later resigned.

Despite the findings of the internal investigation, four training officers within the department determined that the use of force was justified and the city's police union has criticized the discipline.

Spoerl, who is challenging the dismissal, declined to comment Friday and his attorney did not respond to a request for comment.